Flexible display device

ABSTRACT

A flexible display device comprises a flexible substrate including a display area and a non-display area; a display layer in the display area on a first surface of the flexible substrate; a polarizing plate on the display layer; and a cover coat in the non-display area on the first surface of the flexible substrate, the cover coat including a first end portion overlapping with the polarizing plate. At least a portion of the non-display area of the flexible substrate and the cover coat are bendable in a bending direction.

This application claims the benefit of Korean Patent Application No.10-2015-0114888 filed on Aug. 13, 2015, the entire contents of which areincorporated herein by reference for all purposes as if fully set forthherein.

BACKGROUND OF THE INVENTION

Field of the Invention

The present disclosure relates to a flexible display device.

Description of the Related Art

Display devices have been used in, among others, computer monitors,televisions, and cellular phones. Such display device include an organiclight emitting diodes (OLED) display device, a plasma display panel(PDP) display device, and others that emit light without a separatelight source, and a liquid crystal display device and others thatincorporate a separate light source.

Recently, a flexible display device has been receiving attention as anext generation display device. A flexible display may be manufacturedby forming a display panel (or a display layer), wiring, and otherelements on a flexible substrate, which is made of a flexible material,such as plastic, so that an image can be displayed under a bentcondition like paper.

The flexible display device may have a variety of applications, not onlyin a computer monitor or a TV but also in a personal mobile device.Accordingly, a flexible display device having reduced volume and weightwhile exhibiting a wide display area has been studied.

In such a flexible display device, a crack may occur in the flexiblesubstrate or the wiring due to various causes when the display device isbent. This crack in the flexible substrate or the wiring may cause afailure of the flexible display device.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a flexible displaydevice that substantially obviates one or more of the problems due tolimitations and disadvantages of the related art.

An object of the present invention is to provide a flexible displaydevice capable of preventing or minimizing cracks in a flexiblesubstrate or wiring when the flexible display device is bent. Anotherobject of the present invention is to prevent or minimize a failure in aflexible display device.

Additional features and advantages of the invention will be set forth inthe description which follows, and in part will be apparent from thedescription, or may be learned by practice of the invention. Theobjectives and other advantages of the invention will be realized andattained by the structure particularly pointed out in the writtendescription and claims hereof as well as the appended drawings.

To achieve these and other advantages and in accordance with the purposeof the present invention, as embodied and broadly described, a flexibledisplay device may include: a flexible substrate including a displayarea and a non-display area; a display layer in the display area on afirst surface of the flexible substrate; a polarizing plate on thedisplay layer; and a cover coat in the non-display area on the firstsurface of the flexible substrate, the cover coat including a first endportion overlapping with the polarizing plate, wherein at least aportion of the non-display area of the flexible substrate and the covercoat are bendable in a bending direction.

In another aspect, a flexible display device may include: a flexiblesubstrate including a display area and a non-display area; a displaylayer in the display area on a first surface of the flexible substrate;at least one additional layer on the display layer; and a cover coatdisposed in the non-display area on the first surface of the flexiblesubstrate, the cover coat including an end portion overlapping with theone additional layer and disposed between the display layer and the oneadditional layer, wherein at least a portion of the non-display area ofthe flexible substrate and the cover coat are bendable in a bendingdirection.

In yet another aspect, a flexible display device may include: a flexiblesubstrate including a display area and a non-display area; a displaylayer in the display area on a first surface of the flexible substrate;a bendable cover coat disposed in the non-display area on the firstsurface of the flexible substrate; a first back plate disposed in thedisplay area on a second surface of the flexible substrate opposite thefirst surface; a second back plate disposed in the non-display area onthe second surface of the flexible substrate; and a supporting memberpositioned between the first back plate and the second back plate whenthe flexible substrate is bent in the bending direction.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate example embodiments of theinvention and together with the description serve to explain theprinciples of the invention. In the drawings:

FIG. 1 is a plan view of an example flexible display device according toan example embodiment in a non-bent condition;

FIG. 2 is a cross section of an example flexible display deviceaccording to an example embodiment under a bent condition;

FIG. 3 is a cross section of a flexible substrate, a display layer, anda connection member of a drive integrated circuit of the flexibledisplay device of FIG. 2 under a non-bent condition;

FIGS. 4A to 4C are cross-sections of modified examples of the flexibledisplay device of FIG. 2;

FIG. 5 is a diagram illustrating an example process of manufacturing acover coat of FIG. 2;

FIGS. 6A and 6B are diagrams respectively illustrating a case in whichthe cover coat is normally formed and a case in which the cover coat isabnormally formed based on a process error, when the cover coat isformed by using a jetting process of FIG. 5;

FIG. 7 is a cross section of a flexible display device according to anembodiment of the present invention;

FIGS. 8A to 8C are cross sections of a flexible substrate, a displaylayer, and a drive integrated circuit connection member of the flexibledisplay device of FIG. 7 under a non-bent condition; and

FIGS. 9, 10A, 10B, 11A, and 11B are cross sections of modified examplesof the flexible display device of FIG. 7.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

Reference will now be made in detail to embodiments of the presentinvention, examples of which are illustrated in the accompanyingdrawings. With respect to reference numerals for components throughoutthe drawings, like reference numerals may designate like components eventhough components are shown in different drawings. Further, in thedescription of example embodiments of the present invention, a detailedexplanation of well-known components or functions may be omitted toavoid unnecessarily obscuring the subject matter of the presentinvention.

Further, in describing components of the present invention, terms suchas first, second, A, B, (a), (b), and so on may be used. Unlessotherwise specified, these terms are used only to differentiate thecomponents from other components such that the nature, order, sequence,or number of the corresponding components is not limited by these terms.Also unless otherwise specified, it is to be understood that when oneelement is referred to as being “connected to” or “coupled to” anotherelement, it may be directly connected to or directly coupled to anotherelement, or indirectly connected to or coupled to another element thoughyet another element “intervening” therebetween, or “connected to” or“coupled to” another element via still another element.

In this specification, a flexible display device broadly refers to adisplay device with a flexible substrate, and broadly encompassesdevices that may be referred to as a bendable display device, a rollabledisplay device, an unbreakable display device, a foldable displaydevice, and other similar devices. In this specification, a flexibleOLED display device is an example of a flexible display device.

In this specification, the display device may have a display area and anon-display area. The display area is an area in which an image or thelike is displayed, and the non-display area is an area, such as a bezel,in which an image is not displayed.

FIG. 1 is a plan view of a flexible display device according to anembodiment when the display device is not bent. As shown in FIG. 1, aflexible display device 100 includes a flexible substrate 110, wiring120, and a display layer or display panel 130.

The flexible substrate 110 is a substrate that supports various elementsof the flexible display device 100, and has softness or flexibility. Theflexible substrate 110 may be referred to as a soft substrate, a firstsoft substrate, or a flexible member. When being made of plastic, theflexible substrate 110 may be referred to as a plastic film, a plasticsubstrate, or a first soft substrate. The flexible substrate 110 may beformed in the shape of a rectangular parallelepiped, but is not limitedthereto and can be formed in various shapes.

The flexible substrate 110 is made of soft material. For example, theflexible substrate 110 may be a film including one selected from a groupof polyester-based polymer, silicone-based polymer, acrylic polymer,polyolefin-based polymer, and copolymer of them. Specifically, theflexible substrate 110 includes one selected from a group ofpolyethylene terephthalate (PET), polybutylene terephthalate (PBT),polysilane, polysiloxane, polysilazane, polycarbosilane, polyacrylate,polymethacrylate, polymethylacrylate, polymethylmetacrylate,polyethylacrylate, polyethylmetacrylate, cyclic olefin copolymer (COC),cyclic olefin polymer (COP), polyethylene (PE), polypropylene (PP),polyimide (PI) polymethylinethacrylate (PMMA), polystyrene (PS),polyacetal (POM), polyetheretherketone (PEEK), polyester sulfone (PES),polytetrafluoroethylene (PTFE), polyvinyl chloride (PVC), polycarbonate(PC), polyvinylidene fluoride (PVDF), perfluoroalkyl polymers (PFA) astyrene acrylic polymer nitro rilko (SAN), and a combination of them. Insome example embodiments when the flexible display device 100 isimplemented as a transparent flexible display device, the flexiblesubstrate 110 is formed of a transparent soft material.

The flexible substrate 110 may include a display area (DA) and anon-display area (NA). The display area (DA) of the flexible substrateis an area in which a real image is displayed, and the non-display area(NA) of the flexible substrate 110 is an area in which an image is notdisplayed.

The non-display area (NA) of the flexible substrate 110 may be an areaextending from the periphery of the display area (DA) of the flexiblesubstrate 110. The non-display area (NA) of the flexible substrate 110may be an area extending from a side of the display area (DA) of theflexible substrate 110. For example, when the display area (DA) of theflexible substrate 110 is formed in a polygonal shape, the non-displayarea (NA) of the flexible substrate 110 may extend from a side of thedisplay area (DA) of the flexible substrate 110. A non-display area (NA)of the flexible substrate 110 which extends from a side of the displayarea (DA) of the flexible substrate 110 is illustrated in FIG. 1 as anexample for the convenience of description, but is not limited thereto.Therefore, the non-display area (NA) of the flexible substrate 110 mayextend from a plurality of sides of the display area (DA) of theflexible substrate 110.

As the non-display area (NA) of the flexible substrate 110 may bedisposed in peripheral areas or edge areas of the display area (DA) ofthe flexible substrate 110, and various circuits for displaying imagemay be arranged therein, the non-display area (NA) may be referred toas, among others, a peripheral area, a peripheral circuit area, an edgearea, or a bezel area.

The display layer 130 may be disposed in the entire area or a portionarea of the display area (DA) of the flexible substrate 110. The displaylayer 130 is an element for displaying a real image and may be referredto as an image display layer. The display layer 130 described herein asan example is an organic light-emitting display layer that includes anorganic light-emitting device to display an image via an organiclight-emitting layer and a thin film transistor to drive the organiclight-emitting device. However, the display layer 130 is not limited tosuch a specific example and broadly encompasses a display layer capableof displaying an image.

The thin film transistor of the display layer 130 may include, forexample, an active layer, a gate insulating layer, a gate electrode, anintermediate insulating layer disposed on the gate electrode and theactive layer, and a source electrode and a drain electrode electricallyconnected to the active layer. The organic light-emitting device mayinclude a first electrode electrically connected to any one of thesource electrode and the drain electrode, an organic light-emittinglayer disposed on the first electrode, and a second electrode disposedon the organic light-emitting layer.

Various elements not directly displaying an image may be disposed in thenon-display area (NA) of the flexible substrate 110. Examples of theelements disposed in the non-display area (NA) of the flexible substrate110 include, among others, various drive integrated circuits, such as agate drive integrated circuit (IC) and a data drive integrated circuit(IC), and a drive circuit section. Here, the various drive ICs and thedrive circuit section may be mounted in the flexible substrate 110 in aGate in Panel (GIP) format, or may be connected to the flexiblesubstrate 110 in a Tape Carrier Package (TCP) or a Chip On Film (COF)format.

The wiring 120 may be disposed on the flexible substrate 110. The wiring120 may electrically connect the display layer 130 disposed in thedisplay area (DA) of the flexible substrate 110 to the drive circuitsection, or to the gate drive IC and the data drive IC disposed in thenon-display area (NA) of the flexible substrate 110 for signaltransmission.

The wiring 120 is formed of a conductive material, and is formed of aconductive material with excellent softness or flexibility in order tominimize the occurrence of a crack when the flexible substrate is bent.For example, the wiring 120 may be formed of a conductive material withexcellent softness such as gold (Au), silver (Ag), aluminum (Al), andthe like. However, components of the wiring 120 are not limited thereto,and the wiring 120 may be formed of one of various conductive materialsused in manufacturing the display layer 130, such as molybdenum (Mo),chrome (Cr), titanium (Ti), nickel (Ni), neodymium (Nd), copper (Cu), analloy of silver (Ag) and magnesium (Mg), or other similar conductivematerials used in manufacturing the display layer 130. The wiring 120may be formed in a multilayered structure including one or more of thevarious conductive materials described above. For example, the wiring120 may be formed in a three-layered structure of titanium (Ti)/aluminum(Al)/titanium (Ti), but is not limited thereto.

At least a portion of the non-display area (NA) of the flexiblesubstrate 110 may be formed in a shape that is bent in a bendingdirection. Here, at least the portion of the non-display area (NA) ofthe flexible substrate 110 having a shape that is bent in the bendingdirection is referred to as a bend area. As the non-display area (NA) ofthe flexible substrate 110 is not configured to display an image, thenon-display area (NA) does not need to include display elements on theupper surface of the flexible substrate 110 and at least a portion ofthe non-display area (NA) may be bent. For the convenience ofdescription, FIG. 1 illustrates an example in which the entirenon-display area (NA) of the flexible substrate 110 is a bend area.However, the bend area is not limited thereto, and only a portion of thenon-display area (NA) of the flexible substrate 110 may be the bendarea. For the convenience of description, FIG. 1 illustrates an examplein which the non-display area (NA) of the flexible substrate 110 isslightly narrower than the display area (DA) of the flexible substrate110, but the non-display area (NA) of the flexible substrate 110 may besignificantly narrower than the display area (DA) of the flexiblesubstrate 110.

The bend area, which is at least a portion of the non-display area (NA)of the flexible substrate 110, may be formed in a shape that is bent inthe bending direction. In FIG. 1, the bending direction is a lateraldirection of the flexible substrate 110. Thus, FIG. 1 illustrates anexample in which the bend area is at least a portion of the non-displayarea (NA) of the flexible substrate 110 that is bent in the lateraldirection of the flexible substrate 110.

Hereinafter, various examples of flexible display devices under a bentcondition will be described with reference to the accompanying drawings.FIG. 2 is a cross section of an example of a flexible display deviceunder a bent condition. FIG. 3 is a cross section of a flexiblesubstrate, a display layer, and a connection member of a driveintegrated circuit of the flexible display device of FIG. 2 under anon-bent condition. As shown in FIGS. 2 and 3, a flexible display device200 may be bent in a shape in which at least a portion of a non-displayarea (NA) of a flexible substrate 210 is bent in a bending direction.

A display layer 230 is disposed on a display area (DA) of a firstsurface 210 a of the flexible substrate 210. A cover coat 240 may bedisposed on the non-display area (NA) of the first surface 210 a of theflexible substrate 210 to prevent moisture permeation or crackoccurrence. The cover coat 240 may be disposed in the bend areadescribed with reference to FIG. 1.

A drive integrated circuit (IC) connection member 250 may be disposed onthe non-display area (NA) of the first surface 210 a of the flexiblesubstrate 210. Various drive integrated circuits, such as a gate or datadrive IC, a drive circuit section, and the like, may be mounted on thedrive IC connection member 250. The drive IC connection member 250 maybe at least one of the tape carrier package (TCP) and the chip on film(COF). The wiring 120 illustrated in FIG. 1 is disposed on the flexiblesubstrate 210, but is not shown in FIGS. 2 and 3 for the convenience ofdescription.

The cover coat 240 is disposed between the display layer 230 and thedrive IC connection member 250, and may cover a portion 230 a of thedisplay layer 230 and a portion 250 a of the drive IC connection member250.

A polarizing layer 232 may be disposed on the display layer 230, but isnot limited thereto. A over coat layer 236 may be disposed on thepolarizing layer 232, with an adhesive layer 234 bonding the polarizinglayer 232 and the over coat layer 236 together.

At least a portion of the non-display area (NA) of the flexiblesubstrate 210 and the cover coat 240 may be bent in the bendingdirection. On a second surface 210 b of the flexible substrate 210opposite the first surface 210 a, a first back plate 260 a and thesecond back plate 260 b may be disposed. The first back plate 260 a maybe disposed to correspond to the display layer 230. The second backplate 260 b may be disposed to correspond to the drive IC connectionmember 250 and be positioned under the first back plate 260 a when theflexible substrate 210 is bent in the bending direction.

A supporting member 270 may be positioned to be in contact with a bendarea of the second surface 210 b of the flexible substrate 210 betweenthe first back plate 260 a and the second back plate 260 b in thevertical direction to support the flexible substrate 210. A head 270 aof the supporting member 270 may have a semicircular shape with ashorter radius than that of the bent flexible substrate 210. Therefore,the head 270 a of the supporting member 270 may be in surface to surfacecontact with the bend area of the second surface 210 b of the flexiblesubstrate 210.

When the flexible substrate 210 is bent in the bending direction,tension is created in the flexible substrate 210. In the flexiblesubstrate 210, the most powerful tension is created in the bendingdirection and may cause a crack in the flexible substrate 210 itself.Also, a crack may occur in the flexible substrate 210 due to an externalimpact. Further, the crack may propagate to the display layer 230. Sucha crack of the flexible substrate 210 may also cause breaking of thewiring (not shown) disposed in the non-display area (NA). The wiring(not shown) may be positioned in an intermediate surface by using thecover coat 240 so that a crack in the wiring can be prevented in a bentstate of the flexible display.

In the flexible display device 200, a bend of the display layer 230 maybe needed to reduce the bezel area, and the cover coat 240 may be formedto prevent moisture permeation and cracks in the bend area. It ispossible to prevent cracks by positioning the head 270 a of thesupporting member 270 to contact the bend area of the second surface 210b of the flexible substrate 210 to support the bend area.

As illustrated in FIGS. 4A and 4B, the head 270 a of the supportingmember 270 may be configured to be a semicircular shape having a radiussubstantially equal to the radius of the bend area of the flexiblesubstrate 210 in the flexible display device 200 described above so asto position the head 270 a of the supporting member 270 to be entirelyin surface to surface contact with the second surface 210 b of theflexible substrate 210 and to improve the stability and curvaturereliability of the supporting member 270. Therefore, it is possible toimprove the effectiveness of the supporting member 270 in preventingwiring cracks in the entire bend area of the second surface 210 b of theflexible substrate 210.

As illustrated in FIG. 4C, the supporting member 270 may not include thehead 270 a in surface to surface contact with the bend area of thesecond surface 210 b of the flexible substrate 210. This exampleconfiguration may reduce or prevent wiring cracks that may be caused byan impact on the flexible substrate 210 by the supporting member 270.

The cover coat 240 may be formed by using various materials throughvarious processes. For example, as illustrate in FIG. 5, the cover coat240 may be formed by coating organic resin (for example, acrylic resin)through a jetting process. The display layer 230 and the wiring (notshown) are formed in the display area (DA) and the non-display area (NA)of the flexible substrate 210, respectively. Then, the drive ICconnection member 250 with one or more drive ICs may be disposed on theflexible substrate 210 and connected to the wiring. The cover coat 240may be formed by coating the organic resin 410 over the flexiblesubstrate 210 between an end 230 a of the display layer 230 and an end250 a of the drive IC connection member 250 using a jetting apparatus400, and performing a hardening process by using ultraviolet (UV) or thelike.

FIGS. 6A and 6B respectively illustrate an example in which the covercoat 240 is normally formed and an example in which the cover coat 240is abnormally formed based on a process error, when the cover coat 240is formed with the jetting process of FIG. 5.

As illustrated in FIG. 6A, when the cover coat 240 is formed through thejetting process, as described above, the organic resin 410 for the covercoat 240 is to be coated on the end 230 a of the display layer 230, andis not to be coated on the polarizing layer 232 on the display layer 230or on the adhesive layer 234 for bonding the polarizing layer 232 andthe over coat layer 236 together. As illustrated in FIG. 6B, due to aprocess error of the jetting process, the organic resin 410 may becoated on the polarizing layer 232 on the display layer 230 or theadhesive layer 234 for bonding the polarizing layer 232 and the overcoat layer 236 together. If the organic resin 410 is coated on theadhesive layer 234 for bonding the polarizing layer 232 and the overcoat layer 236 together due to the process error and is hardened, an airgap may occur between the adhesive layer 234 and the over coat layer 236when bonding the over coat layer 236 with the polarizing layer 232 withthe adhesive layer 234 due to a portion of the cover coat 240 protrudingover the adhesive layer 234. Bubbles may occur between the adhesivelayer 234 and the over coat 236 layer, potentially causing adhesionfailure of the over coat layer 236 or panel failure.

Hereinafter, example embodiments of a flexible display device capable ofpreventing or mitigating adhesion failure of an over coat layer or panelfailure, even when a cover coat is formed over a flexible substrate withthe jetting process, will be described with reference to theaccompanying drawings.

FIG. 7 is a cross section of the flexible display device in a bent stateaccording to an example embodiment of the present invention. FIG. 8C isa cross section of a flexible substrate, a display layer, and a drive ICconnection member of the flexible display device of FIG. 7 under anon-bent condition. As shown in FIGS. 7 and 8A to 8C, a flexible displaydevice 700 according to the example embodiment may include a flexiblesubstrate 710 having a display area (DA) and a non-display area (NA)extending from the display area (DA), a display layer 730 disposed inthe display area (DA) on a first surface 710 a of the flexible substrate710, a polarizing layer 732 disposed on the display layer 730, and acover coat 740 disposed in the non-display area (NA) on the firstsubstrate 710 a of the flexible substrate 710.

The flexible display device 700 may include a first back plate 760 athat is disposed on a second surface 710 b of the flexible substrate 710to correspond to the display layer 730, and a second back plate 760 bthat is disposed on the second surface 710 b of the flexible substrate710 opposite the first surface 710 a and separated from the first backplate 760 a.

The flexible display device 700 may include a supporting member 770positioned between the first back plate 760 a and the second back plate760 b in the vertical direction, and separated from the flexiblesubstrate 710 in the vertical direction. As illustrated in FIG. 7, thehead 770 a of the supporting member 770 in a bent state may have asemicircular shape with a radius smaller than a radius of the flexiblesubstrate 710 in a bent state, and be in contact with the second surface710 b of the flexible substrate 710, similar to the example shown inFIG. 2. Alternatively, the head 770 a of the supporting member 770 mayhave a semicircular shape with a substantially same radius as the radiusof the bent flexible substrate 710 so as to be substantially entirely insurface to surface contact with a bend area of the second surface 710 bof the flexible substrate 710, similar to the examples shown in FIGS. 4Aand 4B. Such alternative configurations may improve stability andcurvature reliability of the supporting member 770. Here, the supportingmember 770 may have a similar configuration as any one of the examplesupporting members 270 shown in FIGS. 2 and 4A to 4C, including theexample of FIG. 4C in which the supporting member 770 does not have thehead 770 a.

As illustrated in FIG. 1, wiring may be disposed on the flexiblesubstrate 710. The wiring may electrically connect the display layer 730disposed in the display area (DA) of the flexible substrate 710 to thedrive circuit section, or to the gate drive IC and the data drive ICdisposed in the non-display area (NA) of the flexible substrate 710 forsignal transmission. The wiring is formed of a conductive material, andmay be formed of a conductive material with excellent softness orflexibility in order to minimize cracks when the flexible substrate 710is bent.

A drive IC connection member 750 may be connected to the wiring in thenon-display area (NA) of the flexible substrate 710, and the cover coat740 may be disposed over the flexible substrate 710 between the displaylayer 730 and the drive IC connection member 750. As illustrated in FIG.7, the cover coat 740 may be positioned between the display layer 730and the drive integrated circuit connection member 750. As describedabove, the drive IC connection member 750 may be one of the tape carrierpackage (TCP) or the chip on film (COF).

At least a portion of the non-display area (NA) of the flexiblesubstrate 710 may be positioned to have a shape that is bent in abending direction. The flexible display device 700 may include the covercoat 740 that is disposed in the non-display area (NA) on a firstsurface 710 a of the flexible substrate 710 and positioned to have ashape bent in the bending direction. The cover coat 740 may also bepositioned to have a shape bent in the bending direction similarly tothe bent portion of the non-display area (NA) of the flexible substrate710.

An intermediate surface may be disposed between the portion of thenon-display area (NA) of the flexible substrate 710 positioned to have ashape that is bent in a bending direction and the cover coat 740.Specifically, the wiring positioned in the non-display area (NA) of theflexible substrate 710 may form the intermediate surface as a dint inthe flexible substrate 710 or the cover coat 740. When the portion ofthe non-display area (NA) of the flexible substrate 710 and the covercoat 740 are bent in the bending direction, a position at which strainson the portion of the non-display area (NA) of the flexible substrate710 and the cover coat 740 caused by the bending become zero or nearzero may be referred to as the intermediate surface.

A polarizing layer 732, an over coat layer 736, and a first adhesivelayer 734 for bonding the polarizing layer 732 and the over coat layer736 together may be disposed on the display layer 730. As illustrated inFIG. 8A, in a manufacturing stage in which the display layer 730 and thepolarizing layer 732 are disposed in the display area (DA) of theflexible substrate 710 and the drive IC connection member 750 isdisposed in the non-display area (NA) of the flexible substrate 710, anorganic resin may be coated over the flexible substrate 710, from an end750 a of the drive IC connection member 750 in the non-display area (NA)of the flexible substrate 710 to an end 730 of the display layer 730 andan end 732 a of the polarizing layer 732 in the display area (DA) of theflexible substrate 710, with the jetting process of FIG. 5. Then, theorganic resin may be hardened to form the cover coat 740.

Next, as illustrated in FIGS. 8B and 8C, an end 740 a of the cover coat740 may be disposed on the end 730 a of the display layer 730 and theend 732 a of the polarizing layer 732. The first adhesive layer 734 maybe disposed on the polarizing layer and the end 740 a of the cover coat740. Then, the over coat layer 736 may be disposed on the first adhesivelayer 734 to be bonded to the polarizing layer 732 via the firstadhesive layer 734. Next, a support structure of the first back plate760 a, the second back plate 760 b, and the supporting member 770 may bedisposed on the second surface 710 b of the flexible substrate 710.Then, a bend area of the flexible substrate 710 may be bent so that theflexible display device 700 in a bent state as illustrated in FIG. 7 maybe obtained.

In the flexible display device 700 illustrated in FIG. 8A, for example,the cover coat 740 may be formed with the jetting process before bondingthe first adhesive layer 734 to the polarizing layer 732. Thus, if theorganic resin 410 is coated over the polarizing layer 732 due to aprocess error, the end 740 a of the cover coat 740 would be positionedbetween the polarizing layer 732 and the first adhesive layer 734 on thepolarizing layer 732. As a result, an air gap does not occur between thefirst adhesive layer 734 and the over coat layer 736. Thus, it ispossible to minimize or prevent adhesion failure of the over coat layer736 or panel failure caused by the air gap occurring between the firstadhesive layer 734 and the over coat layer 736.

As illustrated in FIG. 9, the flexible display device 700 may furtherinclude a barrier layer 738 between the display layer 730 and thepolarizing layer 732. If the flexible display device 700 includes thebarrier layer 738, the end 740 a of the cover coat 740 may be positionedbetween the polarizing layer 732 and the first adhesive layer 734 on thebarrier layer 738 and the polarizing layer 732. Specifically, the end740 a of the cover coat 740 may be positioned on the end 732 a of thepolarizing layer 732 between the polarizing layer 732 and the firstadhesive layer 734, and on an end 738 a of the barrier layer 738.

As illustrated in FIGS. 10A, 10B, 11A, and 11B, the flexible displaydevice 700 may include a second adhesive layer 739 between thepolarizing layer 732 and the display layer 730 in place of or inaddition to the barrier layer 738. The flexible display device 700 mayinclude the second adhesive layer 739 between the polarizing layer 732and the display layer 730 or the barrier layer 738. The end 740 a of thecover coat 740 may be positioned between the polarizing layer 732 andthe first adhesive layer 734 as shown in FIGS. 8B and 8C, between thedisplay layer 730 and the second adhesive layer 739 as shown in FIG.10A, or between the second adhesive layer 739 and the polarizing layer732 as shown in FIG. 10B.

As illustrated in FIG. 10A, if the barrier layer 738 is not included,the end 740 a of the cover coat 740 may be positioned between thedisplay layer 730 and the second adhesive layer 739 on the display layer730. Specifically, the end 740 a of the cover coat 740 may be positionedbetween the display layer 730 and the second adhesive layer 739 on theend 730 a of the display layer 730.

Alternatively, as illustrated in FIG. 10B, if the barrier layer 738 isnot included, the end 740 a of the cover coat 740 may be positionedbetween the second adhesive layer 739 and the polarizing layer 732 onthe second adhesive layer 739. Specifically, the end 740 a of the covercoat 740 may be positioned between the second adhesive layer 739 and thepolarizing layer 732 on the end 739 a of the second adhesive layer 739.

As illustrated in FIG. 11A, if the barrier layer 738 is included, theend 740 a of the cover coat 740 may be positioned between the barrierlayer 738 and the second adhesive layer 739 on the barrier layer 738.Specifically, the end 740 a of the cover coat 740 may be positionedbetween the barrier layer 738 and the second adhesive layer 739 on theend 738 a of the barrier layer 738.

Alternatively, as illustrated in FIG. 11B, if the barrier layer 738 isincluded, the end 740 a of the cover coat 740 may be positioned betweenthe second adhesive layer 739 and the polarizing layer 732 on the secondadhesive layer 739. Specifically, the end 740 a of the cover coat 740may be positioned between the second adhesive layer 739 and thepolarizing layer 732 on the end 739 a of the second adhesive layer 739.

In the example embodiments described above, the cover coat 740 ispositioned in the non-display area (NA) on the first surface 710 a ofthe flexible substrate 710, and the end 740 a is disposed under thepolarizing layer 732 or on the polarizing layer 732. That is, the end740 a of the cover coat 740 is disposed on at least one of the displaylayer 730, the barrier layer 738, the second adhesive layer 739, thepolarizing layer 732, and the first adhesive layer 734. In forming thecover coat 740 by coating the organic resin 410 through the jettingprocess of FIG. 5, any one of the display layer 730, the barrier layer734, the second adhesive layer 739, the polarizing layer 732, and afirst adhesive layer 734 may be disposed on the display layer 730 as anelement on which the end 740 a of the cover coat 740 is to be disposed.Then, the organic resin 410 may be coated through the jetting process ofFIG. 5 and hardened to form the cover coat 740.

In the example embodiments described above, the cover coat 740 may bepositioned in the non-display area (NA) on the first surface 710 a ofthe flexible substrate 710, and the end 740 a is positioned under thepolarizing layer 732 or on the polarizing layer 732. As a result, an airgap does not occur between the adhesive layer 734 and the over coatlayer 736. Thus, it is possible to minimize or prevent adhesion failureof the over coat layer 736 or panel failure by a dint or an air gapformed between the adhesive layer 734 and the over coat layer 736.

As illustrated, for example, in FIG. 7, 8A, 8B, 9, 10A, 10B, 11A, and11B, the drive IC connection member 750 may be connected to thenon-display area (NA) on the first surface 710 a of the flexiblesubstrate 710, and the cover coat 740 may cover an end 750 a of thedrive IC connection member 750.

Also, as described above, on the second surface 710 b of the flexiblesubstrate 710, the first back plate 760 a may be disposed to correspondthe display layer 730. The second back plate 760 b may be disposed tocorrespond to the drive IC connection member 750 and may be positionedunder the first back plate 760 a when the flexible substrate 710 is bentin the bending direction. A supporting member 770 may be positionedbetween the first back plate 760 a and the second back plate 760 b inthe vertical direction.

Similar to the examples shown in FIGS. 2, 3, and 4A to 4C, the exampleflexible display device 700 illustrated in FIG. 7 may include at leastone of the first back plate 760 a, the second back plate 760 b, and thesupporting member 770 under a bent condition, but is not limitedthereto. Different variations of the support structure on the secondsurface 710 b of the flexible substrate 710 may be implemented.

According to the example embodiments of the present invention describedabove, it is possible to prevent or reduce cracks in the flexiblesubstrate or wiring when the flexible display device is bent. Also,according to the example embodiments of the present invention describedabove, it is possible to prevent or mitigate adhesion failure or panelfailure in the flexible display device.

The foregoing description and the accompanying drawings of the exampleembodiments of the present invention are provided for illustrativepurposes only and are not intended to limit the scope of the presentinvention. It will be apparent to those skilled in the art that variousmodifications and variations can be made in the flexible display deviceof the present invention without departing from the spirit or scope ofthe invention. Thus, it is intended that the present invention cover themodifications and variations of this invention and of the exampleembodiments described herein, provided they come within the scope of theappended claims and their equivalents.

What is claimed is:
 1. A flexible display device, comprising: a flexiblesubstrate including a display area and a non-display area; a displaylayer in the display area on a first surface of the flexible substrate;a polarizing plate on the display layer; and a cover coat in thenon-display area on the first surface of the flexible substrate, thecover coat including a first end portion overlapping with the polarizingplate, wherein at least a portion of the non-display area of theflexible substrate and the cover coat are bendable in a bendingdirection.
 2. The flexible display device of claim 1, further comprisinga first adhesive layer on the polarizing plate.
 3. The flexible displaydevice of claim 2, wherein the first end portion of the cover coat isdisposed between the polarizing plate and the first adhesive layer. 4.The flexible display device of claim 2, further comprising a secondadhesive layer disposed on the display layer and under the polarizingplate.
 5. The flexible display device of claim 4, wherein the first endportion of the cover coat is disposed between the display layer and thesecond adhesive layer, or between the second adhesive layer and thepolarizing plate.
 6. The flexible display device of claim 4, furthercomprising a barrier film disposed on the display layer and under thesecond adhesive layer, wherein the first end portion of the cover coatis disposed between the display layer and the barrier film, between thebarrier film and the second adhesive layer, or between the secondadhesive layer and the polarizing plate.
 7. The flexible display deviceof claim 1, further comprising: an adhesive layer disposed on thedisplay layer and under the polarizing plate, wherein the first endportion of the cover coat is disposed between the display layer and theadhesive layer, or between the adhesive layer and the polarizing plate.8. The flexible display device of claim 1, further comprising: a barrierfilm disposed on the display layer and under the polarizing plate; andan adhesive layer disposed on the barrier film and under the polarizingplate, wherein the first end portion of the cover coat is disposedbetween the display layer and the barrier film, between the barrier filmand the adhesive layer, or between the adhesive layer and the polarizingplate.
 9. The flexible display device of claim 1, further comprising anover coat layer on the first adhesive layer and bonded to the polarizingplate through the first adhesive layer.
 10. A flexible display device,comprising: a flexible substrate including a display area and anon-display area; a display layer in the display area on a first surfaceof the flexible substrate; at least one additional layer on the displaylayer; and a cover coat disposed in the non-display area on the firstsurface of the flexible substrate, the cover coat including an endportion overlapping with the one additional layer and disposed betweenthe display layer and the one additional layer, wherein at least aportion of the non-display area of the flexible substrate and the covercoat are bendable in a bending direction.
 11. The flexible displaydevice of claim 10, further comprising: a drive integrated circuit (IC)connection member disposed in the non-display area on the first surfaceof the flexible substrate, wherein the cover coat includes a second endportion covering an end of the drive IC connection member.
 12. Theflexible display device of claim 11, wherein the drive IC connectionmember includes at least one of a tape carrier package (TCP) and a chipon film (COF).
 13. The flexible display device of claim 10, furthercomprising: a first back plate disposed in the display area on a secondsurface of the flexible substrate opposite the first surface; a secondback plate disposed in the non-display area on the second surface of theflexible substrate; and a supporting member positioned between the firstback plate and the second back plate when the flexible substrate is bentin the bending direction.
 14. The flexible display device of claim 13,wherein, when the flexible substrate is bent in the bending direction,the supporting member includes an end portion having a semicircularshape and contacting the second surface of the flexible substrate at abent area of the flexible substrate.
 15. The flexible display device ofclaim 14, wherein, when the flexible substrate is bent in the bendingdirection, the semicircular end portion of the supporting member has aradius substantially equal to a radius of the bent area of the flexiblesubstrate so that the semicircular end portion of the supporting membersubstantially entirely contacts the second surface of the flexiblesubstrate a the bent area of the flexible substrate.
 16. The flexibledisplay device of claim 10, wherein the one additional layer is one ofthe polarizing plate, an adhesive layer, and a barrier film.
 17. Aflexible display device, comprising: a flexible substrate including adisplay area and a non-display area; a display layer in the display areaon a first surface of the flexible substrate; a bendable cover coatdisposed in the non-display area on the first surface of the flexiblesubstrate; a first back plate disposed in the display area on a secondsurface of the flexible substrate opposite the first surface; a secondback plate disposed in the non-display area on the second surface of theflexible substrate; and a supporting member positioned between the firstback plate and the second back plate when the flexible substrate is bentin the bending direction.
 18. The flexible display device of claim 17,wherein, when the flexible substrate is bent in the bending direction,the supporting member includes an end portion having a semicircularshape and contacting the second surface of the flexible substrate at abent area of the flexible substrate.
 19. The flexible display device ofclaim 18, wherein, when the flexible substrate is bent in the bendingdirection, the semicircular end portion of the supporting member has aradius substantially equal to a radius of the bent area of the flexiblesubstrate so that the semicircular end portion of the supporting membersubstantially entirely contacts the second surface of the flexiblesubstrate a the bent area of the flexible substrate.
 20. The flexibledisplay device of claim 17, further comprising: at least one additionallayer on the display layer, the at least one additional layer being oneor more of a polarizing plate, an adhesive layer, and a barrier film;and a drive integrated circuit (IC) connection member disposed in thenon-display area on the first surface of the flexible substrate, whereinthe bendable cover coat includes: a first end portion overlapping withthe at least one additional layer, and disposed between the displaylayer and the at least one additional layer in the display area of theflexible substrate; and a second end portion covering an end of thedrive IC connection member in the non-display area of the flexiblesubstrate.